A new class of organic-inorganic hybrid materials were prepared by combining Cu-HMS with a silylation agent, trimethylchlorosilane (TMCS) via a simple silylation process at different silylation temperatures. They were characterized by a series of techniques including FT-IR, powder XRD, Nitrogen adsorption-desorption, TG analysis and water adsorption capacity test. It was demonstrated that silylation of PdCl2/Cu-HMS catalysts with TMCS enhanced their hydrophobicity, improved their activity and stability and importantly kept the excellent selectivity to diethyl carbonate (DEC) by oxidative carbonylation of ethanol in the gas-phase reaction. Moreover, the silylated samples obtained at 60 A degrees C showed a better conversion of EtOH of 6.1 % and STY of DEC of 140.8 mg g(-1) h(-1).